2025/04/13 by Lokesh Chander, C. P. Singh, Chander, Lokesh +1 · 1 citation
Physics and Astronomy · #Cosmology and Nongalactic Astrophysics (astro-ph.CO) #FOS: Physical sciences #General Relativity and Quantum Cosmology (gr-qc) #Relativity and Gravitational Theory
paper · pdf · doi:10.48550/arxiv.2504.09523
openalex publication_date 2025/04/13 · openalex created_date 2025/10/18 · openalex updated_date 2026/07/28
We discuss an interacting dark sector model featuring decaying vacuum energy and dark matter empowered by gravitationally induced matter creation. Motivated by quantum field theoretic considerations of vacuum decay and adiabatic particle production, we analyse both the background dynamics and the growth rate of perturbations. The model is confronted with diverse datasets, including Cosmic Chronometers, Pantheon Type Ia Supernovae, Baryon Acoustic Oscillations, Cosmic Microwave Background distance priors, weighted linear growth rate measurements and an H0 prior, with parameter estimation performed via Markov Chain Monte Carlo (MCMC) methods. Model comparison is carried out using the Akaike and Deviance Information Criterion. Our results show a consistent transition from a decelerated to an accelerated expansion phase, with present Hubble parameter estimates lying between the Planck and SH0ES values, thereby easing the Hubble tension. The structure growth parameter S8 is also compatible with Planck 2018 and recent weak lensing surveys. A thermodynamic analysis confirms consistency with the generalized second law, and including Casimir contributions provides further insights into the model's dynamics. Overall, the proposed model effectively captures the Universe's evolution at both theoretical and observational levels.